This study expects to see an alteration in the regular oscillatory frequency of pulsatile insulin secretion in patients with GDM and that these changes will persist after the conclusion of the pregnancy. However, because of the resolution of insulin resistance associated with pregnancy, we would expect that the Bergman MINMOD parameters will tend to normalize in the postpartum period in those patients with regular pulsatile insulin secretion, while remaining in those with abnormal pulsatility.